3.1" Cobaltoan Calcite/Cobaltocalcite Rough w/Malachite Natural Mineral Cluster Stone Crystal Rock Specimen - Congo (#2) You will receive exactly this Cobaltoan Calcite Rough - 79mm x 51mm x 37mm / 3 1/8 x 2 x 1 7/16 Inches; 285g / 10.1 oz (see photo, the photos are taken under bright light, stand not included, the last photo is taken under UV light)! Cobaltocalcite is a variety of Calcite, the most stable polymorph of calcium carbonate, the other polymorphs are the minerals Aragonite and Vaterite. Cobaltocalcite contains impurities of cobalt. Calcite has many varieties of crystal and massive shape and form, and occurs in all colours. Cobaltocalcite is known as Cobaltoan Calcite and Sphaerocobaltite and forms wonderful rose pink crystal specimens. Calcite, which gets its name from chalix the Greek word for lime, is a most amazing and yet, most common mineral. It is one of the most common minerals on the face of the Earth, comprising about 4% by weight of the Earths crust and is formed in many different geological environments. Calcite can form rocks of considerable mass and constitutes a significant part of all three major rock classification types. Chemical Formula: (Ca,Co)CO3; Hardness: 3; Mineral Group: Carbonates; Mineral Species: Calcite; Colour: Pale to deep pink; (The above information is provided solely for informational purpose. Kindly note that all stones are offered for decorative purposes only. Please, handle your stones with great care, do not grind or crumble them, do not dip or add them into your food or drink, do not use any parts of them in any elixirs, potions, lotions etc. Always make sure you wash your hands before and after working with your crystals.)